The B8 type structure of Cu7In3

A neutron and X-ray powder diffraction study of B82 related superstructure phases in the Ni–In system

“…The fractional coordinates and isotropic atomic displacement parameters (ADP's) were then refined using starting values for Ni 13 Ga 9 and Cu 7 In 3 taken from literature [15][16][17][18][19]. The ADP's were in general refined individually to check for "unusual" behaviour.…”

“…It was hoped that the sharper peak profiles and longer wavelength used to collect the XRD data might alleviate problems with overlapping reflections. All three powder profiles were initially refined using the reported fractional co-ordinates of the (assumed) isostructural Cu 7 In 3 as starting parameters [15]. Correlation problems due to overlapping reflections were somewhat reduced in the case of the 10 K neutron data but even here well-separated peaks could not be obtained.…”

“…Based on the results of this previous investigation [13], the B8 2 related superstructure phases in the Ni-In system appear to be of the structure types Cu 7 In 3 [15,16], Ni 5 Ge 3 [17] and Ni 13 Ga 9 [19] (or Pt 13 In 9 ). Since no refined crystal structures have previously been reported for any of these various B8 related superstructure phases in the case of the Ni-In system, it was decided to synthesize samples of these compositions in the Ni-In system and to refine their crystal structures.…”

On squaring triangles – Structural motifs in Cu–In–Sb compounds

“…Just like HT and LT Cu 5 In 2 Sb 2 , all of these phases have the common structural feature of partial occupation of the trigonal bipyramidal sites. The 35 only exception is Cu 7 In 3 wherein all of these sites are occupied, but where instead In vacancies are formed [9]. An alternative description can be constructed by using the bcc defect packing of γ-brass, by which the structural relation to its cubic γ-brass HT-modification Cu 9 In 4 becomes more 40 apparent [10].…”

“…The 35 only exception is Cu 7 In 3 wherein all of these sites are occupied, but where instead In vacancies are formed [9]. An alternative description can be constructed by using the bcc defect packing of γ-brass, by which the structural relation to its cubic γ-brass HT-modification Cu 9 In 4 becomes more 40 apparent [10]. Having this in mind, one may expect that another border of the η phase field in Cu-In-Sb may be closely related to Cu 7 In 3 rather than to any of the other phases.…”